How export constant keys?
If when exporting your asset you let the bake animation enabled and the sampling rate on 1, then it should put keys on each frame of your animations, removing any interpolation and negating the effects of key type change.
I forgot to mention, Blender's FBX exporter does a keyframe cleanup in its baking, which you might want to remove by setting the &quot;simplify&quot; to 0.